Liquid crystal thermometer for MRI

Abstract

Provided herein are novel liquid crystal based devices for the facile measurement of temperature in an MRI system. The thermometers comprise a plurality of vessels wherein each vessel contains a liquid crystal composition having a unique phase transition temperature. By scanning with appropriate techniques, the state of the liquid crystals in each vessel can be assessed, and the temperature at the time of the scan can be determined by the state of the liquid crystal compositions. Also provided are novel vessels and assemblies of vessels that can be used as MRI thermometers and which are compatible with MRI phantoms.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0001]This invention was made with government support under grant numbers 70NANB14H297 awarded by the National Institute of Standards and Technology. The government has certain rights in the invention.BACKGROUND OF THE INVENTION[0002]Magnetic resonance imaging (MRI) is a powerful platform that enables non-invasive medical imaging with high resolution. MRI enables the diagnosis and assessment of various conditions such as cancer, neurodegenerative and musculoskeletal diseases. However, for MRI to be effective as a diagnostic tool, the measurement protocols must yield consistent results across different MRI systems. Differences in MRI hardware, software platforms and user implementation of imaging protocols produce variability in measurements across different systems or even at different time points for the same system. Such variability can lead to misdiagnosis or inconclusive findings.[0003]Accordingly, there is a need to...

AI Technical Summary

Benefits of technology

Provides a cost-effective and non-invasive means to accurately measure temperature, ensuring consistent characterization of MRI systems and reducing errors in measurements by using liquid crystals with distinct phase transitions detectable by MRI, facilitating standardization across different systems and time points.

Problems solved by technology

Such variability can lead to misdiagnosis or inconclusive findings.

Therefore, variations in MRI bore temperatures, which can span from 15° C. to 25° C., will render the use of phantoms as ground truth standards irrelevant if not accurately corrected for temperature.

These methods are problematic for various reasons.

Fiber-optic thermometers are expensive, require laborious set-up and tear down to implement.

Other temperature sensors are invasive and require human interface with the phantom before and after the scan, and potentially compromise the MRI phantom integrity by introducing unwanted microorganisms into the phantom.

However, for MRI, where the sample sizes and fields of view are large, variations in the magnetic field strength will introduce errors in the chemical shift based thermometer, prohibiting accurate temperature measurement if the thermometer is not reproducibly placed in the exact position, and if variations of the main magnetic field exist between scanners.

The methods disclosed by McRae et al., while useful in the hyperthermic treatment regimen to which they were applied, are insufficient for calibration of phantoms.

Few MRI scanners are equipped with the capability to do the spectroscopic analysis needed for McRae's technique, and obtaining MR spectra is a time consuming process that would not integrate well with the process used to characterize or standardize an MRI using a ground truth tissue mimicking standards.

Furthermore, the signal obtained using McRae's methods is inadequate for the error assessment needs addressed herein due to the much smaller magnetic field used.

Additionally, McRae's implementation required the use of the fluorine 19 to produce measurable signal; such material is expensive and toxic.

Additionally, McRae's method requires the liquid crystals to be microencapsulated, making the transition temperature too broad for the accuracy needed for an MRI calibration thermometer

Images